Motor vehicles typically include passenger protection systems such as airbags or seatbelt pretensioners. Many of these protection systems are triggered by a firing element, for example a pyrotechnic firing cap (squib), which initiates further processes for opening an airbag or for tensioning a seatbelt. Such a firing cap is usually activated by virtue of the fact that a predefined activation current/firing current is applied to it for a predefined activation period by a drive circuit.
Circuit arrangements are known in which two semiconductor switches, with which the firing element is connected in series, are integrated into a common semiconductor body or semiconductor chip. During operation, a supply voltage is applied across the series circuit of the two semiconductor switches and the firing element, and the voltage gives rise to the firing current through the firing element when the two semiconductor switches are switched on.
The integration of the two semiconductor switches on one semiconductor chip can lead to a situation in which, when there is a serious fault on the chip, uncontrolled activation of the passenger protection system occurs. Such a serious fault may include the fracturing of the chip, for example due to thermal or mechanical stresses.